Dipper tooth



Feb. 13,1945.

A. W. DANIELS ET AL DIPPER TOOTH 4 Sheets-Sheet 1 Filed May 1, 1943INVENTORS Feb.13, 1945. M L ETAL 2,369,285

DIPPER TOOTH Filed May 1, 1945 4 Sheets-Sheet 2 q/Zga Feb. 13, 1945. A.w. DANIELS ETAL DIPPER TOOTH Filed May 1, 1945 4 Sheets-$heet 5 Viz i112[W 2 3 Feb. 13, 1945'. A w, 'DAMELS ET AL 2,369,285

PPPPPPPPP TH Filed May 1, 1943 4 Sheets-Sheet 4 Patented Feb. .13, 1945Joseph P. Murtaugh, Oak Park, 111., assignors to Daniels-Murtaugh,Company, Cedar Rapids,

Iowa, a partnership Application May 1, 1943, Serial No. 485,272

1111 Claims. (o1. 37- 142) The teeth of steam shovel dippers and otherpower driven excavating implements wear down with surprising rapidity inspite of the fact that they are made of tough manganese steel and arehardened by the pounding which they receivein service. The abrasivenature of the service to which they are subjected is so severe thatreplacementoi the teeth is a substantial item in the cost of running anexcavating implement.

For many years, it has been recognized that wear. They have tended towear rounded along the bottom front edge until very soon the teeth wouldact like runners of a sled and. ride up on wFig. 2 is a side Fig.1; Fig.3 is a fragmentary vertical sectional View taken. approximately on theline 3-3 of Fig. 1;

Figs. :4, 5 and 6 are side views of modified forms view of the structureshown in of1the rep1aceable points; i

the difiiculty arose not only from the amount of i wear but the shap towhich the teeth would i stay sharp until it is worn back to the point Awhere repointing becomes desirable. Without turning the teeth upsidedown, they will last considerably longer than previous teeth even whenthe latter were turned upside down, and

during their entire life, they will be muchmore satisfactory thanprevious teeth. In fact, they may even be sharper almost to the end oftheir life than conventionalteeth when they. are new.

In general, this result is accomplished by providing a shape which,although providing adequate strength, causes the tooth to wear flatinstead of rounded on its bottom front edge.

At the same time, this new shape facilitates welding new points to theold tooth, saving both time and welding rod. This results from the factthat the channel formed in the bottom of the tooth in order to balancethe wear and produce the flat bottom or self-sharpening wearing effectFig. 7 is a bottom view of the point shown in Fig. 6;, illustrating,however, optional features of shape for all 01 the illustrated points;

. Figs. 8, 9, 10 and 11, are views illustratinga modified form of theinvention, Figs. -8 and 9 being perspective views showing the repointed.H

tooth respectively right side up and upside down, and Figs. 10 and 11,respectively, being side and bottom views of therepointer; l l

. Figs. 12, 13, 14 and 15 are viewsof another form of theinventioncorresponding respectively to Figs. 8 to 11;

Fig. 16 is a perspective view showing drag-line bucket equipped withteeth embodying the presentinvention, some; of them having beenrepointed.

Several forms of the invention have been chosen for illustration anddescription, in compliance with- Section 4888 of the Revised Statutes,but persons; skilled the art will. readily perceive other meansforaccomplishing the same results, and th claims are therefore to beconstrued as broadly as possible, consistent with the prior art.

' teeth maybe removably secured as illustrated or they may be ofanyform. The particular form e illustrated is one including a body portionI2 need not be welded and intact forms a clear H demarkation to show thewelder where to weld and where not to weld.

In one form of the invention, the repointer and the base portion of thetooth are provided with interfitting V-type parts whichaccuratelyposition the tooth for welding so thatthe teeth will beproperly alinedin their digging function.

Additional objects and advantages of the invention will be apparent fromthe following de scription and from the drawingsin which:

Fig. 1 is abottom view of the embodiment of the invention chosen forillustration of the form. thereof at present preferred;

havingits upper and lower faces converging toward the point, and a shankportion I3 provided with a key slot l4 through which a key 15 (Fig.

The body portion includes wings l6,

sides. The base should be complementally shaped with clearanceseverywhere except .at

these converging surfaces. Thus, the tooth {will be rigidly held by thebase, vertical shifting being prevented by the V engagement seen in alongitudinal vertical plane, and lateral shifting being prevented-bytheV engagement seen in a section perpendicular to the longitudinal axis ofthe tooth.

.- When the teeth of'Figs' l to 8 are originally sold, they may be-asingle casting or forging, and

require a departure from smoothness.

the body portion I2 will be extended to the point. The contour of theoriginal tooth may be approximately as shown for the composite tooth inFigs. 1 and 2 or it may be quite difierent. Of course, the top'andbottom converging faces of a new tooth would usually be smooth exceptinsofar as special features of shape might After the point has been worndown on one side, the tooth may be turned over to wear the point down onthe other side, although this is not usually necessary with the presentinvention.

When the tooth becomes worn to a point where it becomes unsatisfactory,a new point 2|, called a repointer, is welded thereto. Usually it willbe necessary to trim the bodyportion l2 with a torch (burn it) to theproper shape to permit the welding. The new tooth is preferably providedwith a guiding ridge 20 to serve as a pattern. The preferred shape thatthe body portion I 2 should have prior to welding is clearly shown inFig. 2'. The tooth is burned straight across between pattern ridges 20.

It will be observed that the point 2| does not fit snugly around the endof the body portion [2. In fact, each of them is of generally convexconfiguration. The purpose of this is to give access for welding.Usually the portion 22 will be filled in by welding first, thusproviding an integral structure from the center line of the tooth to thetop face of the tooth. This entire gap will be filled in solidly asshown. Next, the portion 23 shown in Fig. 3 will be welded in all theway across the tooth. The provision of the groove 24 inthe underface ofthe tooth indicates to the welder the depth to which this weld 23 shouldbe extended all the way across the tooth. Thereafter the portions 26will :be'filled in by welding, thus providing a continuation of each rib21 at the two sides of the groove 24. This method of welding provides aconstruction which has been found to have adequate strength for heavyduty excavating implements.

An even more important function of the groove 24 is in causing the toothto wear sharp. It will be obvious that as the ribs 21 wear o1f,'thetooth will be considerably thinner than if-the channel 24 had been solidmetal and the wear distributed all along this solid metal. From onestandpoint, it might be said that the provision of channel 24 causesabalanoe in the wear of the'tooth so that it wears thinner at therightspeed to keep step with its wearing shorter. The tooth cannot bemade thinner initially for it-would not have adequate strength. The ribs21 give 'adequate strength to the point although they wear down fastenough so that the tooth may be said 'to be self-sharpening. In short,the provision of the groove 24 extending to the tip of thetooth and ofincreasing width and depth rearwardly causes the vertical or upwarddiminution of the tooth to keep pace quite well with the rearwarddiminution, so that for aconsiderab'le period: of wear the thickness ofthe front end of the tooth is not excessive or, in other words,'-thetoot stays reasonably sharp.

Having the tooth reduced in thicknessto keep step with its shorteningmay not be quite the whole story since teeth in the past have had atendency to wear rounded to the shape of a sled runner. The presenttooth largely avoids this and it is believed that there are two factorswhich contribute toward it, one .being the provision of the channel 24and the ribs 21" and the other being the initial shaman-mg of thetoothwitha the tooth is being slid forwardly in the digging operation.It should be borne in mind that one common use of drag-line buckets forexample is to strip coal or other material from a rock strata.

As seen in Fig. 1, the front end portion 29 of j the ribs 2'! isconsiderably wider than the rearward portion of the ribs 21. This hasbeen found to increase both the strength and the wearing qualities ofthe forward portion of the point without disadvantage, since the toothremains sharp as this portion of the tooth wears. It is desirable toshape the ribs so that they will wear just'fast enough at each stage ofwear to keep the tooth sharp.

Of course the exact shape which would be ideal from the standpoint .ofwear might vary somewhat with the nature of the digging operation. Allof the shapes shown have been found to be fairly satisfactory. Thoseshown in Figs. 10, .11, 14 and 15 are now preferred, it being noted thatthe width of the groove 24 at the up is approximately thirty percent ofthe width of the tooth at .the tip. Further back, where the ribs Z'lhavegreater depth to wear down, the groove is relatively wider and hence theribs relatively narrower.

The groove 24 is valuable from the standpoint of efficient use of metalas Well as from the standpoint of longer life. Even if the point becamedull slightly faster with the groove 24 than without, there would stillbe the advantage of using fewer'pounds of point for a given number .ofhours of operation .than if the groove 24 were not provided.

The groove 24 has been shown as continued into the body portion of thetooth as at 3|. is not necessary but avoids having a projection whichmight strike rocks as the tooth is moved forwardly. When new teeth areprovided with a groove 24in casting, the groove will naturally beextended back fora gradual termination, as shown. However, when thetooth is not originallyso formed, it will be optional whether or not thecontinuation groove 3| is burned into the body portion.

The shape of the tooth shown in Figs. .1 to 3 is at present thepreferred shape. The radius of longitudinal curvature of the faces 32 isabout eight to ten inches, although it is'not at all objectionable for.the upper face to be flat. The face 33 inside the groove has beenillustrated as being fiat at the front portion and then curved fromthere rearwardly. The various teeth are drawn approximately to scale. Ofcourse, the size and shape of point will depend somewhat on the shapeand size of the tooth for whichit is designed, and in any eventvariations may be This takes place. ures, the repointer may be weldedtothebase first 2,369,285 21 have a flattaper 38 instead of a curved conEach of these features, the forwardly widened point and the flatlytapered rib, isoptour.

tional with the different shapes of vertical cross section shown. l i

The repointer could of course be a little thicker at its rear end thanhas been shown sothat it would correspond in thickness more to anextension of the body 12, indicated by the dotted lines 4|. However, itis preferred tohave the repointer slightly slimmer than the distancebetween the lines 4! so that the projecting ridge 42 will form atransverse guide for burning oif the tooth to receive a new repointer. Anew tooth is preferably of the same shape as the repointed toothhereshown soas to provide guide ridge [42 as well asthe demarcation or ridge2t. Even if ridge d2 should be worn 01f slightly before a repointer wasapplied, the wear would produce a visibleguide line.

In the form of tooth shown in Figs, 8 to 11, means is provided forcorrectly positioning the all of the teeth will be properly aligned. Theproper alignment of the various teeth on a dipper is desirable partly toinsure the self-sharpening wear of the teeth so that the dig line willbe i straight and horizontal. The latter reason is tooth repointer onits base during welding so that especially important where a rock stratais being stripped of coal since it is desirable to clean the "coal fromthe rock as thoroughlyas possible.

As is perhaps most clearly seen in Fig. 8, the

tooth base 5! is provided on each side with a small recess 52, the topand bottom faces of which converge slightly rearwardly to form aV-shaped notch. The repointer 53 is provided with correspondingly shapedtongues 54. Because of their V-type of engagement with the recesses 52,the tongues 54 accurately align the repointer 53 with thebasefil.

This not only positions the repointer accurately but also holds it whilethe welding process As in the case of the previous figalong the bottomas at 5% and then along the top as at 58, or vice versa.

Usually the base 5: will be suppliedwith the recess 52 cast therein andthe repointers 53 will,

of course, always be formed by casting or otherwise with the tongues 5 3there-on when they are to be used with the base 5!. Of course if bases5! having the recess 52 therein are not available, such recesses can becut in old worn teeth with a cutting torch.

In Figs. 12 to 15, another form of repointer has been shown which has anadvantage of simplified welding. The welding is simplified be-. causealthough it extends over longer lines, there is no plane of cleavage andthe welded bead may be much thinner.

In this instance, therepointer BI is provided with rearwardly diverginglegs Gland 63. The leg 63 is provided with an, opening 64 therethroughwhich serves the dual purpose of continuing the groove 24 and permittingaccess, to.

align the repointer and help hold it in position for welding. l l l lThe legs 62 and 63 do a large shareof holding the repointer. on the baseand since there is no plane of cleavage, a minimum of welding will besufficient. To a lesser'extent, this same advantage is'obtained in thestructures of Figs. 8 to 11 since the tongues 54 interrupt the plane ofcleavage which would be present without said tongues and to the extentof theirstrength reduce the amount of welding necessary.

From the foregoing it is seen that a tooth point-shape is provided whichmakes the tooth self-shapeningin wear, and makes it sufiiciently" strongto withstand heavy duty. Furthermore tooth repointers (preferably ofthis shape) and methods of welding the same to the tooth base have beenprovided which effect a tremendous saving in metal as compared toreplacement of the teeth, which may be welded so easily that the cost ofwelding is much less than heretofore, and

which in the preferred forms are self-aligning prior to welding. V iFig. 16. shows another invention ofapplicants which may be describedhere very briefly since it is a divisible invention and will be thesubject of another application. Thisrefers to the shape of thedrag-linebucket 6|. An important feature is that the foremost parts ofthe bucket are heavy hitch plates 62. The tips 63 of these hitch platesextend beyond the mounting facili-.

ties for hitch links 64 so as to serve as bumpers when the bucket isdropped to th ground in dumped position (front end first). The hitchlinks 64 automatically fold in so that the chain connected to them willnot be injured. The arch 66 rises vertically from apoint forward of theteeth but rearward of the bumpers 63 so that it rarely strikes theground. Furthermore, its center portion 61 is shaped to be approximatelyaligned with the direction "of movement of the bucket in being droppedso that if it does strike it will strike fully edgewise and hence not becaved in. The balance of the bucket is exceptional. 1 l l i We claim: 1.A tooth repointer for excavating implements and thelike, having upperand lower faces con verging forwardly toward the tip and having alongitudinally extending groove of such dimensions that innormal use ofthe point the upward diminution of the point will keep pace with therearward diminution sumciently closely to maintain reasonable sharpnessof the tooth asit wears rearwardly a substantial distance from theoriginal tip, the downwardly exposed face within the groove beingapproximately parallel to the upper faceof the point for approximatelyat least one inch rearwardly from the tip of the point, and the groovewidening rearwardly from the tip as it deepens, said repointer-beingconvexly shaped on its rear end to facilitate welding it "to a basetooth portion, and said groove being open at the rear end, thusdemarking anarea which neednot be welded.

2. A tooth repointer for excavating implements and the like, havingupper and lowerfaces converging forwardly toward the tip and having alongitudinally extending groove of such dime'nsions thatin normal use ofthe point the upward diminution of the point will keep pace with therearward diminution suificiently closely to maintain reasonablesharpness of the tooth as it wears the tooth base 66 isproperlyshaped itwillbe observed that the legs Bland 63 will properly rearwardly asubstantial distance from'the original tip, said repointer beingconvexly shaped on.

its rear end to facilitate Welding it'to a base tooth portion, and saidgroove being open at the rear end, thusdemarking an area which need notbe welded. i

3. A tooth for excavating implements and the like including opposedfacesconverging forward- 1y toward a tip to form a point, and having contourchanges forming demarcations rearwardly of the pointadapted to serve asguides for burning, off the point along a path which will leave a convexsurface on the'front end of the remainder of the tooth appropriate forwelding theretoa repointer having a convex rear face.

4. A tooth repointer for excavating implements and the like, havingupper and lower faces converging forwardly toward the tip and havingalongitudinally extending groove of such ;dimen- ,sions that in normaluse of the point the upward diminution of the point will keep pace withthe I rearward diminution sufficiently closely to maintain reasonablesharpness of the toothas it wears rearwardly a substantial distance fromthe original tip, and the tip of the tooth sloping downwardly andforwardly substantially to the bottom of the tooth whereby the tooth isself-shapening as it wears, said repointer being convexly shaped on itsrear end to facilitate welding mm a base tooth portion, and said groovebeing open at the rear end, thus demarking an area which need not bewelded. and a tongue formed on the rear of the repointer with rearwardlyconverging faces to fit in a correspondingly shaped pocket of a memberto which it is to be welded to properly align the repointer thereon.

5. A tooth repointer for excavating implements and the like, havingupper and lower faces converging forwardly toward the tip and having alongitudinally extendinggroove of such dimensions'that in normal use ofthe point the upward diminution of the point will keep pace with therearward diminution sufiiciently closely to maintain reasonablesharpness of the tooth as it wears rearwardly a substantial distancefrom the origbeing convexly shaped on its rear end to facilitate of asuitable metal for tooth points, shaped to form a tooth point, withopposed faces two of which converge toward the front end, and havingrear face portions converging from opposed faces approximately to anintermediate point to permit access for welding between the said rearaeeaess faces andthe generally convex end of the body portion of atooth, and a tongue formed on the rear of the repointer with rearwardlyconverging faces to fit in a correspondingly shaped pocketof a member towhich it is to be welded toproperly align the repointer thereon.

7. A tooth repointer for excavating implements and the like, havin upperand lower faces converging forwardly toward the tip and having at leastone longitudinally extending groove in the lower face extending, at onelongitudinal position, over half the width of the tooth and approximately half the thickness of the tooth, and including legs divergingrearwardly to fitover a correspondingly shaped tooth base portion forwelding thereto, said groove forming an opening through one leg to giveaccess to welding near the tip of the nose. l

8. A tooth repointer for excavating implements and the like, havingupper and lower faces converging forwardly toward the tip and having alongitudinally extending groove, said repointer welding it to a basetooth portion, and said groove being open at the rearend, thus demarkingan area which need not be welded.

'9. Atooth for excavating implements and the like, including a base andarepointer welded thereto and having upper and lower faces con-- vergingforwardly toward the tip and having a longitudinally extending groove,said repointer and base being convexly shaped on their adjacent ends tofacilitate welding them together, and said groove being open at the rearend of the repointer, thus demarking an area which need not be welded.

10. A tooth for excavating implements and the like including a basehaving a generally convex end, and a repointer comprising a block of asuitable metal for tooth points, shaped to form a tooth point, withopposed faces two of which converge toward the front end, and havingrear face portions converging rearwardly from op- .posed facesapproximately to. an intermediate point to permit access for weldingbetween the said rear faces and the generally convex end of the base,and a tongue formed on the rear of the repointer with rearwardlyconverging faces and fitting in a correspondingly shaped pocket in thebase, said tooth being welded to the base in the f alignment determinedby said tongue and pocket.

11. A tooth base for excavating implements and the like having a convexend adapted to have a repointer Welded thereto and having asmall pocketin a forward portion of the end with rearwardly converging faces to fita V-shaped tongue on the rear of the repointer which is to be welded tothe base to properly align the repointer on the .base.

ARTHUR W. DANIELS. JOSEPH P. MURTAUGH.

